Spot remover compositions for use on fabric materials such as clothing, carpets and upholstery have existed for many years, for example, see British Patent No. 1,397,475 to Loudas. These types of products are used on relatively small areas of fabrics to remove soil and stains due to food or oily materials. Water-based stains require polar solvents while oily soil or stains require relatively nonpolar solvents for proper removal. These solvents are often difficult to combine into a homogeneous composition.
For convenience, aerosol formulations are used so the user can simply spray the composition onto the fabric. Preferably, the compositions can remove the stain without appreciably wetting the fabric which can spread the stain out rather than removing it. Drying time is often critical for garment spot removal because the stain is often only noticed at the time the garment is to be worn. "Dry" cleaning compositions are also important where the garment is sensitive to water and must be commercially dry cleaned rather than simply laundered in water. In addition to long drying times, significant amounts of water to remove stains can cause shrinkage and warping of carpeting and also may promote mold growth. Thus, it would be desirable to have an aerosol composition that can spot dry clean fabrics without leaving the fabric wet to a significant degree.
Many attempts to provide self-pressurized aerosol spot dry cleaning compositions for fabrics have been made. The flammability of such compositions is of concern since the hydrocarbon solvents that are useful in removing oil-based stains tend to be flammable as are the lower alkyl hydrocarbon propellants used in conventional self-pressurized aerosol spray formulations. Halogenated hydrocarbon propellants are not flammable, but have fallen into disfavor due to their adverse ecological impact on the atmosphere.
U.S. Pat. No. 3,161,460 to Huber teaches a self-pressurized aerosol degreasing agent composed of a solvent for fat and grease like difluoromethane or monochloro difluoromethane and a finely divided solid absorbent such as talcum powder, silica gel or siliceous earth. One solvent must be a low boiling solvent such as a fluorinated solvent, unsubstituted aliphatic hydrocarbon, aliphatic alcohol or ketone. The compositions can be used to dry shampoo human hair as well as to spot clean textiles.
U.S. Pat. Nos. 3,925,010 and 3,794,590, each to Barton, teach spot dry cleaning compositions for textile fabrics that use an azeotropic mixture of water, tertiary amyl alcohol and tetrachloro difluoroethane as the cleaning agent. The vapors of the azeotropic mixture are stated as non-flammable.
U.S. Pat. No. 3,714,049 to Charle et al. teaches self-pressurized aerosols composed of a stain removing agent such as a chlorinated hydrocarbon with an isopropanol diluent or a hydrocarbon, a finely divided solid absorbent such as "silicon" powder or talcum powder, and a propellant such as a saturated lower aliphatic hydrocarbon or halogenated hydrocarbon where either or both the stain removing agent and the absorbent are microencapsulated.
U.S. Pat. No. 4,013,595 to Podella et al. teaches non-flammable aqueous aerosol rug cleaners using flammable hydrocarbon propellants such as isobutane, n-butane and propane. They possess reduced flammability due to the presence of at least 0.3% lauryl alcohol in combination with 0.3-10% of an alkali metal lauryl sulfate salt as at least one of the surfactants. These compositions would not be suitable for spot dry cleaning of fabrics since they contain 50-90% water.
In view of the disadvantages of hydrocarbon propellant-based and halogenated hydrocarbon propellant-based products, dimethyl ether has been proposed as an alternative propellant for self-pressurized aerosol products as described in "Roundtable Discussion: Du Pont talks about its DME propellent, Part I," Aerosol Age, May, 1982, pp. 20ff. and "Dimethyl ether as a propellant in hair sprays, L. J. M. Bohnenn, Aerosol Age, June, 1983, pp. 36ff. These articles teach that dimethyl ether can be used as a propellant in place of conventional propellants and has the further advantage of allowing the use of significant amounts of water in such formulations. The water reduces the flammability of the products. Since dimethyl ether is miscible in water up to about 34%, homogeneous aqueous solutions can be formed. To obtain a wide range of homogeneous solutions, a cosolvent such as ethanol can be added to provide water miscability in all proportions. U.S. Pat. Nos. 4,584,021; 4,597,895; and 4,600,530, each to Bartlett, describe the use of various corrosion inhibitors to permit packaging of aqueous dimethyl ether-propelled aerosol formulations in tin-plated aerosol cans.
Japanese Kokai Patent Application No. HEI 2[1990]-202978 to Onizuka et al. teaches an aerosol static inhibitor for treating fiber fabrics in the home. It uses dimethyl ether as the propellant along with ethanol and 6-45% water to deliver a static inhibitor compound such as sodium polyoxyethylene lauryl sulfate to the fibers. This product is used to treat fabrics rather than to clean them.
U.S. Pat. No. 3,207,386 to Presant et al. teaches a non-flammable self-pressurized aerosol dispenser that uses dimethyl ether as a propellant in place of hydrocarbon or halogenated hydrocarbon propellants. The dispenser uses relatively large amounts of water in combination with the dimethyl ether propellant to carry an active ingredient so the spray is said to be non-flammable. The active ingredients are selected to provide hair grooming sprays, paints, window cleaner sprays, foods, nasal sprays and the like. The maximum water solubility of dimethyl ether in water is said to be 35.3% at 24 C. at 5 atmospheres of pressure.
U.S. Pat. No. 3,694,546 to Roth et al. teaches a two-phase aerosol spraying system using dimethoxymethane because it is said to be an excellent solvent for carbon dioxide and nitrous oxide propellants. Example 3 of the '546 Patent uses silica and dimethoxymethane along with acetone and xylene as a stain remover where the propellant is carbon dioxide.
U.S. Pat. No. 4,243,548 to Heeb et al. teaches a self-pressurized aerosol formulation using at least 50% by weight of non-combustible constituents where the propellant is carbon dioxide and dimethyl ether. The formulations must additionally contain at least one of the following non-combustible constituents: water, carbon dioxide, methylene chloride or 1,1,1-trichloroethane. Dimethoxymethane is said to be useful as a solvent for the propellants. Water is preferably 12.9-18% by weight of the total formulation.
U.S. Pat. No. 4,322,037 to Heeb et al. teaches an aerosol container to spray compositions that are free of chlorofluorinated hydrocarbon or hydrocarbon gases. The container can be used to deliver liquids pressurized by dimethyl ether as a propellant. Dimethoxymethane is suggested as a possible solvent for the propellant or the active ingredients to be delivered. The compositions preferably contain 12.9-18% water. Use of chlorofluorinated solvents is preferred in one embodiment although chlorofluorinated propellant gases are to be avoided. Another preferred carrier composition is composed of 54.0-55.0% water, 0.9-1.1% carbon dioxide, 38.5-35.1% dimethyl ether and 9.0-6.4% alcohols having 2 or 3 carbon atoms. The compositions delivered from such containers can be hairsprays, room sprays and cosmetic or medicinal sprays such as deodorants.
As can be seen from the above, various different ingredients have been used in self-pressurized aerosol spray formulations, but none of the above suggests a self-pressurized spot dry cleaning composition that is effective against oil-based stains, and possesses reduced flammability compared with conventional aerosol spray compositions pressurized with lower aliphatic hydrocarbon propellants that are free of undesirable chlorinated or fluorinated solvents and propellants and does not leave the fabric noticeably wet after using.